A volcano on the equator in the Pacific Ocean;
and on its very rim, among the lava boulders life;
a giant tortoise.
Inside another, in its very throat,
an iguana climbs down the walls to lay its eggs on the floor of the crater.
Yet this is one of the most active volcanoes on earth.
Closer to the coast, molten lava spouts from yet another vent.
And here, alongside a lava flow, lives another iguana.
Like creatures from some creation myth
these reptiles manage, astonishingly,
to live among the fires that build the earth.
The Galapagos Islands are home to the only sea-going lizard in the world
the marine iguana.
In spite of the crashing surf,
the iguanas manage to graze on lush growths
of marine algae that flourish around the coasts.
After an hour or so in the sea,
these lizards have to come to land to warm up again in the sun.
Getting ashore is not always easy.
This is the coast of Fernandina,
the most westerly and the newest of the Galapagos Islands
and home to the biggest concentration of marine iguanas.
It's January, the beginning of the hot season,
the time for them to begin to breed.
Big males roam aggressively through the herd of females,
establishing their breeding territories
and that means battling with rivals.
Shaking the head is a challenge and one that has to be met.
While the larger males were fighting,
a subordinate has moved in to mate with a female.
The big male regularly surveys his territory
and he's spotted the trespasser.
This cannot be allowed.
He drags the female away
and carries her off to the center of his domain.
Once the female receives his sperm,
she will become unreceptive and will not mate again this year.
The intruder will have to try again elsewhere.
The iguanas congregate in herds around the coastal areas
where there is easy access to the sea and the riches it contains.
There are fifteen main islands in the Galapagos archipelago.
In contrast to the sea around them,
they are largely barren and dominated by craters and lava fields.
All, over the last five million years,
have been built by volcanoes erupting from cracks in the earth's crust,
deep below on the floor of the ocean, a process that still continues today.
Rivers of molten rock pour down the volcano's flanks,
lighting the equatorial night with their glow.
Nothing can stand in their path
as they flow inexorably downhill into the sea.
When dawn comes,
it reveals that the lava has run right through a grove of palo santo trees,
the home of a pair of Galapagos hawks and a large colony of land iguanas.
Some of the survivors are making their escape
across the cooling fringes of the lava
but at the cost of scorching their feet.
Others were not so lucky.
On the coast, the lava created more havoc among the wildlife.
Birds lost their regular roosts but they were able to fly to safety.
Many of the marine iguanas, however, were boiled alive in the sea.
Only a few escaped and now a completely new landscape faces them
and the flightless cormorants.
It's February. On a nearby beach,
the female marine iguanas are digging holes.
Four weeks ago, they had mated and now it's time to lay their eggs.
Hawks have appeared in the mangroves beside the beach.
The arrival of the hawks has not gone unnoticed.
Out on the beach, the females are exposed and exhausted from digging.
It's time for them to leave.
As the hawks take off,
the female iguanas run for a place where they'll be safe... the sea.
The hawk may have tackled too heavy a victim.
The outcome is by no means a foregone conclusion.
The female will still have a chance if only she can get to the water.
And finally the hawk gives up but the iguana is dead.
The males, being bigger,
are usually safe from attack and have been basking
in the sun before going into the water
They have particularly long claws that enable them to cling to the rocks
and resist the pull of the swell as they rip off the algae.
Although these are air-breathing animals,
they regularly remain underwater for ten minutes at a time.
But they seldom stay out at sea for longer than an hour
because they get chilled and lose their energy.
Little wrasse swim alongside them,
gathering the small creatures disturbed as the algae is pulled up.
Schools of baitfish have appeared.
They are pursued by sea-lions,
descendant from immigrants that came down
from California in the distant past.
Sea-lions, like iguanas, are air breathers.
But being mammals, they generate their own body heat
and so they're able to spend long hours in the water.
March and warmer waters flow down from the north,
raising the temperature of the sea.
Evaporation from the ocean surface increases
and clouds build up above the islands.
Soon there will be rain.
All the inhabitants of the Galapagos
seem to appreciate the refreshment that it brings.
For the land iguanas, inland from the coast,
it brings the rare chance of a drink.
Isabela, the largest of the islands, has had rain for several weeks
and pools have formed on the floor of its central volcano, Alcedo.
The giant tortoises take in gallons
and store it in their bladders as a reserve for the droughts ahead.
The hawks are beginning their courtship flights.
The tortoises too, after feasting on the newly sprung grass,
will soon begin their mating.
The males are all somewhat bigger than their mates,
but this one has picked a particularly diminutive partner.
A young hawk seems baffled by these heaving boulders.
It's trick and apparently exhausting business
and the groans of the males carry for miles,
echoing around the crater.
Alcedo is only one of six large volcanoes on the island of Isabela.
Each has its own population of tortoises that,
being separated by barren fields of lava
have in isolation, evolved their own individual characters.
Fernandian, west of Isabela,
once had tortoises too but none survive there today.
It is, however, a stronghold of the marine iguanas
and the eggs they laid on the beach,
warmed by the sun, are now hatching.
For the great blue heron, this is a good time.
For the hatchlings, there is hundred metres of open sand to cross
before they reach the safety of the water.
Herons are not the only enemy they have to face.
Galapagos snakes don't kill their victims with venom...
they squeeze them to death.
But first they have to catch them.
In order to reach the sea,
some young iguanas must first cross an old lava flow.
The snakes know this
and several of them are there, waiting in ambush.
The snake can unhinge its lower jaw
and engulf prey that is stouter than itself.
Death comes to the young iguana from suffocation.
Some iguanas find safety in deep cracks that have formed in the lava.
That crack was just not narrow enough.
The ancestral iguanas are thought to have arrived in the Galapagos
as involuntary passengers from South American,
on floating vegetation, several million years ago,
and while one branch of their descendants stayed beside the sea,
another took to the hills.
In patches of vegetation on the lower slopes of Fernandina
the land iguanas are now gathering to breed.
Each male has dug a number of burrows and the females come to inspect them.
Her nod, however,
is an aggressive 'no' rather than a submissive 'yes'.
But he persists.
Now she seems almost indifferent to him.
She allows a mockingbird to clean her
by picking off dead bits of her skin-which it then eats.
She makes a meal from one of the plants growing on the male's land.
He's beginning to lose patience.
This is not the place to mate.
It's better to take her to the center of his territory,
where he is least likely to be interrupted.
His contribution to the partnership is almost finished.
When they separate he'll stay here and wait for another female to turn up.
But her labours are only just beginning,
For now she sets off on a quite extraordinary journey.
She starts to ascend the flanks of Fernandina
going up to towards the crater.
She'll have to climb up to fifteen hundred metres above sea level
and the journey to the top will take her ten days... or more.
Close to the rim of the crater, steam spouts from fumaroles
and this keeps the ash warm and moist
the perfect place though that town to inherit eggs.
She follows a well-worn path up to the nesting ground.
Hundred have already been this way in the last week or so.
Suitable ground is limited and much of it already occupied.
She spots an area that seems vacant...
but it's not.
There seems to be no room for her here
The sun is beginning to set.
At this altitude, the nights can be very cold
and that's bad for a reptile
She has to find shelter.
A small cave just the place.
Others are already inside, but nonetheless she's allowed in.
The temperature begins to fall dangerously.
But steam, percolating from below, keeps the dormitory snugly warm.
In the cool morning air, steam swirls upwards,
Heated from the magma chambers below.
But the nesting ground is fully occupied.
She and other late comers have to move on.
There's only one place to go now
over the lip of the crater and down into it
Fernandina crater I immense.
Eruptions emptied the lava chamber deep below
and the top of the mountain collapsed, forming this huge caldera.
No-one knows when it will explode again.
The walls of the crater have not yet stabilized after the last eruption
and are continually collapsing.
She and her companions start on what seems to be a suicidal journey.
They descend into the crater.
The crater floor is almost a kilometer below.
The walls are steep and dangerously unstable.
The slightest disturbance can send tons of rocks hurtling downwards
and each year the iguanas have to find new paths down.
Many of the migrants are killed each year but still they come.
At last they reach the crater floor.
Ash lies thickly here.
In some areas steam from below keeps it warm
and there, just below the surface,
it's a constant 30 degrees centigrade the perfect temperature
to incubate iguana eggs.
There is more room down here.
But any attempt to dig in a place
that might disturb the eggs already been buried there
will lead to violence. She must be cautious.
A place of her own at last.
Even after all this, there is no certainty of success.
Some years, an eruption will destroy all the eggs...
nor are the females' labours yet over.
They still have to climb out of the crater
and trek ten kilometers down the volcano back to their home grounds.
July brings relief from the hot season
Trade winds from the southeast drive cool air up the sides of the volcano
and the moisture they carry condenses into low-lying fog.
This is the garua.
For the next six months,
these mists will be the only source of moisture on the islands.
Twenty-five kilometers to the east of Fernandina lies the Alcedo volcano.
There, the arrival of the garua is the signal for the tortoises
in the crater to climb up to the rim and collect the liquid the mists bring.
There are several kinds of birds up here.
A finch collects ticks from the tortoises,
just as mockingbirds pick skin from the iguanas.
And tortoises invite them to do so by adopting a special posture
so that the birds can reach every possible part of their skin.
Tortoises, after all, can't scratch themselves,
neither can they clean their nostrils,
so this arrangement suits both parties
In the western part of the archipelago
the garua sweeps around the slopes of Fernandian and over the lava fields,
blocking out the sun for several hours each morning.
As the mists burn off,
the marine iguanas begin their daily trip down the beach to the sea.
At this time of the year,
cool currents sweep in from the coast of South American,
a thousand kilometers away to the east and cold rich waters
from the central Pacific often well up from the depths,
producing lush growths of marine algae
The algae grow with phenomenal speed.
And they need to,
for along this stretch of coast live tens of thousands of marine iguanas.
The hatchlings are now three months old
and they feed on the algae exposed on the rocks at low tide.
Sea-lion pups of around the same age don't go out to sea either.
They stay in the shallows, playing boisterously with one another.
And no only with one another.
For them, an iguana seems to be yet another toy.
By early afternoon, most of the iguanas have finished grazing
and are sunbathing to get the heat they need
to be able to digest their meals.
Some of the hatchlings stay together on their own patch of the beach,
but others mingle with the adults.
And that is the safer place to be.
The hawk won't tackle a full-grown male iguana
it's too big and powerful.
A young hatchling, however, is a different matter.
A young reptile dies... and a young bird is kept alive,
for this is also the time that the Galapagos hawk breeds.
There are two chicks in the nest.
The bigger one is always fed first.
Only when it is satisfied will the smaller one get any food.
But this year has been a good one for the iguanas,
so there's plenty of food for both chicks.
Back on the coast, the sea-lions too are giving birth.
The mother tears away the birth membranes
so that her baby can get its first breath of air.
As it breathes, so it calls and that is vitally important,
for the two must learn to recognize the sound of one another's voices
and so be able to find one another in days to come.
The sea-lion's afterbirth is high grade protein
and both crabs and iguanas are quick to claim it.
The rich up welling nutrients along the coast
stimulate the boobies to begin their courtship.
A blue-footed boody needs to show its mate that it has blue feet
and is not any other kind of boody,
and their courtship dances certainly make that quite clear.
In some areas the boobies are breeding
where the marine iguanas traditionally spend the night
and the reptiles have to run a gauntlet of beaks
to get to their dormitories.
As the iguanas settle down to sleep,
they continually spurt liquid from their noses.
This is a salty fluid that drains into their nostrils
from special glands that excrete the salt they take in
with their meals of sea-weed.
The sun begins to sink,
the day cools and the iguanas cluster together to keep warm.
During the night, the garua rolls in across the summit of Fernandina.
At dawn, mist clings to the coast
because of the continued presence of cold water.
It's signal for the penguins to gather and court.
Like the blue-foots, penguins only breed when food is plentiful...
and it has arrived.
The rich waters along the coast have attracted huge swarms of baitfish.
Penguins love baitfish.
One of their tactics is to drive a shoal into shallow water
where there's less room for the fish to manoeuvre.
Forced near the surface, others can dive in from above.
Pelicans.
Once the pelicans have drained the water from their pouches,
they can lift their beaks and swallow their catch
without being pestered by penguins.
But now there are others to trouble them
Noddy terns.
The blue-foots can fish much farther out to sea.
They often detect the presence of a shoal near the surface
by the activities of dolphins...
who are searching for the same thing.
The sea-lions also follow dolphins.
And when at last the prize is discovered,
There's a frenzy of feeding.
Harried from below by dolphins and sea-lions,
the shoal rises towards the surface and gives the blue-foots their chance.
Back on the cliffs,
the young blue-foots are exercising the wings they've not yet used
and playing with the marine iguanas.
Such activities all help to develop
the young boobies' skillsof manipulation
and build up their wing muscles in preparation
for the time when they too will need to catch fish.
The hawk chicks, well nourished on their diet of young iguanas
are now two months old and almost ready to fly
eager, doubtless, to go and find food for themselves.
Last year's broods of hawks gather from all around the island
and demonstrate their competence in the air above the summit of Fernandina.
They're keeping a sharp eye on the floor of the crater below,
for their biggest feast of the year is about to begin.
It's now October, a hundred days since
the female land iguanas were here laying their eggs.
Those should now be on the verge of hatching.
All the hawks are aware of what is about to happen
and all are determined to claim their share.
The first of the hatchlings emerges.
Though totally inexperienced,
they obviously sense the danger posed by the hawks.
The eggs in each clutch hatch almost simultaneously
and the youngsters will stand a better chance
if they all run for cover together.
One decides to make a break for it.
The others see that the attention of the hawks has been diverted.
It's hot work, waiting around.
The ash is now 50 degrees centigrade.
There are just too many talons around to escape them all.
Once they reach the crater wall, there is more cover.
But the hawks can still outwit them.
They are only six inches long;
they have not yet fed and are dependant for their energy entirely
on the little yolk that remains in their belly;
And they still have to climb a crater wall a thousand metres high.
The rim of the crater at last.
But this is only a brief triumph.
Neither the journey nor its dangers are over yet.
A short distance below is the steaming fumarole and nesting area
which their mothers passed three months earlier
on their way into the caldera.
Up to a dozen snakes have gathered here.
Some slither into the burrows where the females had laid their eggs,
listening for the vibrations made by hatching iguanas
as they dig their way up to the surface.
The hatchlings can outrun the snakes if they get a reasonable start.
But the snakes are everywhere.
There are few that make their escape
climb up a plant or a boulder every now
and then to get a better view of the way a head
there is a long way to go get
Their final destination is the vegetated slopes of the volcano,
Thirteen hundred metres below.
Down on the coast, their cousins,
the young marine iguanas, are now six months old
and increasingly confident as they graze among the waves.
It will be several years yet before they're big enough
and strong enough to join their parents cropping on the sea floor.
The reptiles of the Galapagos live in an isolated world.
But it's no island paradise.
They're surrounded at all times by danger from the land,
the sea and the sky.
The very rocks they live on regularly split apart and erupt fire.
But it's these very perils and privations that have changed
and refined these species to such a degree
that today there are no other creatures anywhere else in the world
like the dragons of the Galapagos.